Delivery and pick-up of payloads by helicopter slings allow the aircraft to remain airborne with no landing zone required and also allow the carriage of outsized equipment. Further, long tethers keep the aircraft away from terrain obstacles and rotor-induced visibility problems, such as dust brown-outs or snow white-outs. However, certain problems occur with long tethers. First is the problem of load stability during flight. A long tether can allow a load to oscillate or simply move to a point where the center-of-gravity limits of the aircraft are exceeded. Such a condition will make the aircraft uncontrollable.
Additional hazards occur when pick-up and attachment times are lengthy thereby exposing the aircraft to hostile fire and endangering ground crew members. Similarly, during delivery and release, delays and ground crew actions can expose both aircraft and ground crew to hostile action.
What is needed is a helicopter hook assembly which can provide stability data to the aircraft and which can automate pick-up and delivery of payloads.